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Subject: Re: Crafty opening book

Author: David Blackman

Date: 22:57:38 01/31/00

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On January 31, 2000 at 16:18:35, Dann Corbit wrote:

>On January 31, 2000 at 09:44:09, Harald Faber wrote:

>>BTW has anyone done the conversion from the book.bin and books.bin into a
>>Fritz-tree? I guess not, I don't know of any converter that does this job, and
>>even creating the tree from the pgn-file does not take the priorities...
>
>I don't think it is invertible.  The hash is stored in the book, not the
>position.  You would have to write out some kind of key-file at creation time.

Start at the starting position. Generate all legal moves. Try each legal move
and then generate the hash, see if it matches any in the book. For the ones that
do, generate all legal moves, and so on recursively. You can re-create all the
book positions in time roughly proportional to book size times number of legal
moves in a position times whatever it costs to access a single position in a
crafty book given the hash.

The only bit that looks at all hard is generating Fritz-tree format at the end.
Is that format documented?

I'm not interested in doing this personally since i don't own Fritz. But i did
tree taversals for various reasons with my own hashed book format, until i
decided the book was more trouble than it was worth.



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